Sodium intake in our society is at least an order of magnitude above the physiological requirement. The excess intake, usually as NaC1 (salt) is due in part to the sensory pleasure associated with the taste of salt in food. The studies will provide insight into how and when a preference for salt develops and how that preference is modified ;by changes in salt consumption. The information obtained will be of value in designing programs and strategies for reducing the sodium intake of individuals and populations. The first four studies evaluate the development of human response to salt. In Study 1, parameters of sucking in response to various concentrations of salt solution are measured in 1-5 month old infants to determine the time course of early development of response to salt. Study 2 compares responsiveness to salt taste of groups of infants with different histories of dietary exposure to salt. Studies 3 and 4 focus on older children. Study 3 compares salt preference and sensitivity using paired-comparison tests and other psychophysical procedures in groups of individuals between 3 years of age and adulthood. Pilot data suggest preferences for markedly higher levels of salt in younger children. Study 4 tests the hypothesis that young children with a family history of hypertension have elevated salt preference relative to children with no such family history. Studies 5-7 focus on adult populations and the effects of decreases in sodium consumption on salt taste perception. Study 5 examines the effects on salt use and taste of moderate reduction (50%) in dietary sodium with and without the opportunity to add salt to food. The importance of salt taste stimulation in mediating taste preference changes which occur following dietary sodium reduction is evaluated. Study 6 continues our collaborative work with investigators in Minneapolis on the effects of lowered-sodium and lwoered-sodium/increased-potassium diets on salt taste preferences in middle-aged, hypertensive men. Study 7 evaluates changes in salt taste following sodium depletion induced by a severely sodium-restricted diet coupled with furosemide treatment.